linux-kernel - Re: [RFC] perf/x86: PMU IRQ handler issues

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20140528195528.GQ29957@tassilo.jf.intel.com>
Date:	Wed, 28 May 2014 12:55:28 -0700
From:	Andi Kleen <ak@...ux.intel.com>
To:	Stephane Eranian <eranian@...gle.com>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	"mingo@...e.hu" <mingo@...e.hu>,
	Dave Hansen <dave.hansen@...el.com>,
	"Yan, Zheng" <zheng.z.yan@...el.com>
Subject: Re: [RFC] perf/x86: PMU IRQ handler issues


> Another explanation is that because we ACK the NMI early, we leave the
> door open to other interrupts, incl. NIC, and we are interrupting the execution

PMI executes with interrupts off.

> of the PMU IRQ handler, yet that detour is measured in the PMU handler
> latency, causing more throttling than needed. Is that a plausible scenario too?
> And if so, I think we need to narrow the window for timing errors, by
> acking late
> on all processors and not just HSW.

If you think there's a concrete problem please show an ftrace.

-Andi
-- 
ak@...ux.intel.com -- Speaking for myself only
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/